There is known a differential transmission system adapted to transmit a differential signal pair, comprising signals having opposite phases, in two signal lines forming a pair. Since the differential transmission system has a feature that a high data transfer rate can be achieved, it has recently been put to practical use in various fields.
For example, in the case of using the differential transmission system for data transfer between a device and a liquid crystal display, the device and the liquid crystal display are each provided with a display port connector which is designed according to the display port standard. As this display port standard, VESA DisplayPort Standard Version 1.0 or its Version 1.1a is known.
This display port connector is a kind of differential signal connector and has a first connection side for connection to a connection partner and a second connection side for connection to a board of the device or the liquid crystal display. The configuration of the first connection side is strictly defined by the display port standard in terms of the relationship with the connection partner while the configuration of the second connection side is relatively free. This type of differential signal connector is disclosed in Patent Document 1 (Japanese Patent No. 4439540 (JP-A-2008-41656)) and has a housing and a contact group held by the housing.
As illustrated in FIG. 1, the contact group comprises three ground contacts 1 spaced from one another and two pairs of signal contacts 2. The signal contacts 2 of each pair are disposed between two adjacent ones of the ground contacts 1. Each of the ground contacts 1 has one end 1a and the other end 1b and each of the signal contacts 2 has one end 2a and the other end 2b. On the first connection side of the connector, the one ends 1a of the ground contacts 1 and the one ends 2a of the signal contacts 2 are adjacently arranged along a single straight line. The ground contacts 1 and the signal contacts 2 extend from the first connection side towards the second connection side in parallel to one another and then are perpendicularly bent in the same direction at positions offset from each other. Thus, on the second connection side of the connector, the other ends 1b of the ground contacts 1 are located at both ends of a long side of a trapezoid while the other ends 2b of the signal contacts 2 are located at both ends of a short side of the trapezoid. The other ends 1b of the ground contacts 1 and the other ends 2b of the signal contacts 2 are inserted into through holes of a connection object (such as a board) and connected to the connection object by soldering.
In the above-mentioned contact group, the other ends 1b of the ground contacts 1 and the other ends 2b of the signal contacts 2 are arranged in different rows on the second connection side. It is therefore readily possible to widen a distance or interval between the other ends 1b of the ground contacts 1 and the other ends 2b of the signal contacts 2 within a limited space or distance.